1. Field of the Invention
The present invention relates to complex digital copiers having a communication function, more particularly a network system for copiers to control a switch-on operation of a plurality of copiers which are connected with each other
2. Description of Related Art
As disclosed by Japanese Patent Publication No. SHO 60(1985)-49901, conventionally known is a copier including a clock circuit, a storage for storing a time to open/close a start-up circuit of the copier, a control circuit controlling the open/close of the start-up circuit when detecting that it becomes the open/close time, and a circuit for maintaining power supply to the copier regardless of the above open/close control, wherein the copier controls the open/close at the set open/close time.
This publication describes means for opening and closing the power supply to the copier by use of an inner counter. With this construction, the copier can reduce power consumption.
However, the conventional power supply open/close device has the following problems. With increasing volume of information, there is a tendency of more and more copiers used in an office, a company or the like. In an increasing number of cases, a plurality of copiers are installed on one floor, or a copier or copiers is/are places on each floor of one company.
Under these circumstances, it needs an enormous amount of time to set the open/close control in every copier. Also, even if the power supply is opened at an hour when copiers are used most frequently, all copiers are rarely used at the same time. That results in a waste of power.
Further, where copiers are powered on at the same time, heater lumps of the copiers may be lighted at the same time. The heater lumps are heat sources for fixing devices of the copiers and consume most of the power required by the copiers. As a result, a breaker of a switch-board may be actuated by a mass of rush currents, or a decline in power source voltage may cause a flicker of fluorescent lumps and mis-operation of electric appliances. These problems will be restricted in the future as is evident from the fact that an item of harmonic test has been established for the CE mark which is an European safety standard. It is also difficult to control all copiers together, for example, by an administration department or the like of a company in view of reduction of power consumption.
Other related arts are as follows: Japanese Unexamined Patent Publication No. HEI 7(1995)-72768 discloses an image producing system in which a plurality of image copiers are connected to each other and the maximum power consumption of the whole system is controlled below a predetermined value by detecting a on or off state of fixation heaters of the image copiers.
Japanese Unexamined Patent Publication No. HEI 9(1997)-16032 discloses a drive control device to reduce power consumption of an electro-photographic device on standby so that the total power consumption of the standby electro-photographic device and an operating electro- photographic device does not exceed a predetermined value.